The present invention relates to a filling spout whose flow rate can be adjusted by a single actuator device.
Document FR-A-2 736 339 discloses a filling spout comprising a valve body receiving firstly a valve member which is opened and closed to determine whether or not the substance flows, and secondly a flow-rate adjustment member making it possible to vary the flow-rate inside the filling spout independently of valve member opening, in order to obtain a uniform flow of substance regardless of the degree of opening of the valve member.
In order to enable the valve member and the flow-rate adjustment member to move independently from each other, it is necessary to implement two separate actuator devices controlled in synchronized manner. That requirement not only penalizes filling spout compactness but also makes the control electronics very complex, in particular when the filling machine is provided with a large number of filling spouts, as is generally the case in current filling installations.
A first object of the invention is to provide a filling spout having an adjustable flow rate and that can operate with a single actuator device.
To this end, the invention provides a filling spout having an adjustable flow rate and comprising a valve body receiving a valve member extending facing a valve seat, and a flow-rate adjustment member disposed upstream from the valve member and extending in register with a constriction in the valve body, the valve member and the flow-rate adjustment member being connected to a single actuator device via means allowing limited axial movement by enabling the adjustment member and the valve member to move axially relative to each other to a limited extent.
Thus, by using a single actuator device, it is possible for the valve member and the flow-rate adjustment member to move differently from each other.
In addition, it is known that, due to the impact exerted by the jet of substance on the bottom of a container at the beginning of filling, there is a risk that froth might form, thereby preventing the filling cycle from taking place properly. Similarly, at the end of filling, on closing the valve member, there is a risk that the jet might be deformed, thereby causing splashing on the outside of the container. In order to avoid those drawbacks, the above-mentioned document makes provision to reduce the flow rate through the flow-rate adjustment member when the valve member opens and closes. Unfortunately, by closing the flow-rate adjustment member almost totally, there is a risk that the bottom portion of the filling spout might not be fed sufficiently between two cycles, in particular when the substance is thick.
In an advantageous version of the invention, the means allowing limited axial movement are suitable for enabling the flow-rate adjustment member to be put in position of maximum flow rate or of minimum flow rate, while the valve member is in a closed position. Starting from a position in which the valve member is closed and the adjustment member is in a position of maximum flow rate, it is possible to perform the following steps:
reducing the flow rate to a position of substantially minimum flow rate;
gradually opening the valve member while increasing the flow rate delivered by the flow-rate adjustment member in corresponding manner;
gradually closing the valve member by reducing the flow rate delivered by the flow-rate adjustment member in corresponding manner until the valve member is fully closed; and
putting the flow-rate adjustment member back into its maximum flow rate position.
Thus, on valve member opening, the force of the jet of substance is low due to the flow-rate adjustment member being adjusted to deliver substantially its minimum flow rate so that the impact against the bottom of the container is itself low, and so that the risk of froth forming is minimized. Similarly, on valve member closure, the reduction in the flow rate provided by the flow-rate adjustment member minimizes jet deformation and makes it possible to avoid splashing the outside of the container, and going through a position of maximum flow rate between valve member closure and the following cycle makes it possible to obtain satisfactory feeding of the filling spout downstream from the flow-rate adjustment member.